Oil burner



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J. J. SLQYAN Jun-:s 32, 3.935

OIL BURNER Filed Dec. 1.3, 1930 2 Sheets-Sheet l l l i',

ATTORNEYS www@ June 4, 1935.,

J. J. SLOYAN OIL BURNER Filed Dec. l5, 1930 2 Sheets-Sheet 2 INV BY Q.

M ATTORNEYS Patented June 4, 1935 UNITED STATES PATENT OFFICE OIL BURNER Jerome J. Sloyan, Red Bank, N. Appiieetien December laissaseriel No. 502,055

This invention pertains to the general class of heating devices and particularly to the class of heating devices adapted for burning liquid fuels.

The invention will be described in connection with a particular type of oil burner. However, it is understood that the invention in whole or in part may be applied generally to the burning of liquid and yother fuels.

There are many types of oil burners in use at the present time. Many of these burners, however, are not adapted to be started with fuels of low volatility; are not automatic in starting and require considerable attention and regulation in starting; develop fuel diiculties such as flooding of the carburetor or mixer, flame extinction, etc.; are not adapted to positively ignite vthe fuel; are not suiciently proof against pre-ignition of the fuel and/or are in some other features generally unsatisfactory. Many burners employ `a diaphragm of reticular material such as wire cloth in the path of the'fuel mixture to prevent propagation of the flame back into the mixing device and/or source of fuel. Devices of this character have a tendency to clog or choke due to the deposition of incombustible particles in or about the interstices of the diaphragm. Such diaphragme also have a tendency to burn out due to the fact that the flame is in contact therewith during practically all low rates of burning.

In my invention a fuel'of low volatility and of low grade may be used throughout its operatienl including that of starting; the apparatus requires no attention during operation; starts automatically; ignites the fuel positively; shuts down automatically if flame or fuel difficulties develop; and although it pre-heats the air to a temperature consistent with highest efficiency it does not pre-heat the air to a point where preignition may occur. Expansion joints are provided to allow for unequal expansion of the parts and novel means are provided for attaching certain of the parts together. Novel means are also provided for enriching the fuel for starting.

In the drawings wherein one form of the invention is shown merely for the purpose of illustration;

Figure l is an elevation, chiefly in section, of one form of the device.

Figure 2 is an end view.

Figure 3 is a section on line 3 3 of Figure l.

Referring to Figures l, 2 and 3, at IB is shown a furnace wall through which extends a combustion chamber Ii. To the mouth of the combustion chamber II is secured a combustion chamber I2. The connection between the combustion chamber II and the combustion chamber I2 is preferably such as to form a path for the flame which is more'or less smooth orina stream line so as to avoid any obstruction tothe flame. 'f5 Any means may be provided for connecting the combustion chamber I2 to the furnace or other chamber II in which combustion takesplace. This may take the form of a ring I3 secured to the sheath I4 which in turn is mountedon and 10 secured to a shoulder I2a on combustion chamber I2. Otherwise sheath I4 is spaced from the combustion chamber I2, so as to provide an air passage I5 between the sheath' I4 and the combustion'chamber i 2. Heat insulation I5 may beV 15 provided between the ring I3 and the furnace wall I0 and chamber II, if desired, to prevent undue radiation of heat to the sheath I4 and associated mechanism, the purpose'of which will be hereinafter referred to. v

The sheath I4 is shown formed so as to `r-provide an annular enlargement I1 for the air passage I5. Connection between a blowery I8 and the enlargement I'I is provided through an opening I9 in the sheath I4. vThe blower pipe 20 is 25 preferably placed at an angle, as shown.

The combustion chamber I2 is shown conical in shape. However, it may be shaped like a tulip or like a morning-glory, that is with walls curving away from or toward the longitudinal 30 center line, or it may be shaped otherwise if desired. The walls of the combustion chamber I2 are of course preferably without abrupt projections in order to avoid obstructions in the path o-f the flame. Y 35 The entrance of combustion chamber I2 is shown merging from a straight portion 22,'illus'- trated as being cylindrical in character, but which of course may have any other desired shape. Portion 22 isrshown provided with -a col-4 40` lar 23 having a shoulder 24 to which is secured a sleeve25 which ts over the end 26 of'sheath I4 so as to provide a sliding fit. A packing nut 21 threadedly engages the sleeve 25, thus forming an air-tight sliding connection between sleeve 25 45 and sheath I4. Novel means is thus' provided for absorbing the effects offunequal expansion between combustion chamber I 2 and sheath I4.

'-Sleeve 25 is provided with an opening 29- 'in which is secured the end of tubular member 30 505 which in turn fits into an opening 3| in heating element chamber 32. Chamber 32 has an end 33 fitting over an air conduit 34 and is provided with threads 35 which'accommodate a packing nut 36. Conduit 34 makes a` reversev turn, as 553 illustrated at 38 and is connected to carburetor 39 as illustrated at 40.

Carburetor 39 may be of any standard construction. I have shown a carburetor having an outlet for the combustion mixture which will permit conducting the mixture in a straight line through the path in which it is to be ignited and consumed. However, any other arrangement may be provided.

The outlet of the carburetor is shown connected to the flange 23 yso as to bring the outlet in line with the channel 4I in portion 22.

The general path of the air and eventually of the combustion mixture is therefore as follows:

The air enters from blower I8 into blower pipe 20,

then passes through opening I9 into enlargement I'I of air passage I5, then into the more restricted portion of air passage I5, then in between sleeve 25 and extension 22, then upwardly through tubular member 3G into chamber 32, then through air conduit 34 into carburetor 39 where it is mixed with the fuel oil. From here the resultant combustion mixture passes into combustion chamber I2. After the device is in operation the air in passing around combustion chamber I2 is pre-heated. This pre-heating of the air, of course, materially assists in volatilizing the fuel oil at the carburetor. The arrangement of thev air passage about the combustion chamber I2 in combination with its general shapeV is disclosed and claimed in my co-pending application Serial Number 492,132 filed October 29, 1930. As a result of this arrangement the air is always maintained at a temperature consistent with most efficient operation but is always kept safely below that which will cause pre-ignition, regardless of the quantity of fuel consumed. Briefly, the point of maximum temperature of the air is reached when the entire combustion chamber I2 is filled with ame. As the consumption of fuel lincreases beyond this point the design of the combustion chamber is such that the velocity of the combustion mixture at the entrance of the combustion chamber I2-is greater than the rate of flame propagation backward toward the entrance. The result is that the source of the flame travels to the left, as seen in Figure 1, from right to left into the combustion' chamber I2. In view of the divergence of the walls of the combustion chamber I2 and the progressively increasing cross-'sectional area, the velocity of the unignited combustion mixture begins to decrease until a cross-section is reached at which the velocity of the combustion mixture is equal to the rate of flame propagation. Assuming that each particle of the combustion mixture is traveling at the same velocity, the point at which the flame will start will be in some plane outwardly in the combustion chamber I2, depending upon the velocity of the combustion mixture at the entrance of the combustion chamber. With an increase in the rate of combustion the source of flame moves to the left in the combustion chamber I2, as seen in Figure 1. Consequently a smaller area of the combustion chamber is exposed to the temperature of the flame. This in turn tends to decrease the total quantity of heat transferred from the combustion chamber I2 to the air passing through the air passage I5. At the same time the quantity of air passing through the air passage I is increased due to the increased rate of combustion. This in turn reduces the quantity of heat transferred per unit of air. The result is that the air may have a relatively high temperature at low rates of burning when a high temperature is most needed, and may be made to fall off in temperature as the rate of combustion increases and as the temperature requirements decrease. This construction and the theory of operation are discussed in detail in my co-pending application above referred to.

To bring the air to a proper temperature for starting, I provide a heating element 45 .in the path of the air. Any type of heating element may be employed for this purpose. The one shown is conveniently arranged in chamber 32 Aand is secured in a socket 46 of insulating material which accommodates the screw base 41 of the element 45. One electrode 48 is shown connected to a bolt 49, passing through the base of the socket 46. The other electrode 50 is shown connected to metallic element 5I which passes around the socket 4B and contacts the metallic portion of the screw base of heating element 45, as illustrated at 5I. A cap 52 is conveniently provided for mounting the electrodes 48 and 50.

To place upon the fuel in the carburetor approximately the saine pressure as that of the air entering the carburetor I provide an outlet 55 in air conduit 34 and connect this outlet through pipe 56 with the carbureter. By this arrangement the normal reduction in pressure of the air passing through venturi 51 will cause the proper amount of fuel to issue from jet or jets 58.

To avoid flooding of the carburetor due to faulty operation of the needle valve and/or float of the carburetor I provide an overflow 60 having its opening 6 I of substantially the same height as the proper level of the fuel in the carburetor.

The overflow is connected to a sealed receptacle 62, by means of pipe 63. To make the pressure in the receptacle 62 substantially the same as that in the float chamber I extend the pipe 56 tothe receptacle 62. This will permit free flow of excess fuel from the float chamber by means of gravity through the overflow Ell.

Although a reticulated diaphragm may be employed to prevent propagation of the flame back to the carburetor, I prefer to use a venturi, such as illustrated at 10, for this purpose. This is because reticulated'diaphragms, for instance those made from wire cloth. have a tendency to clog and choke, requiring frequent cleaning, and also have a tendency to burn out more'or less quickly. I find that for all practical purposes a venturi serves the purpose of a reticulated diaphragm, and in addition to this will not clog or choke, does not require cleaning, will not burn out, adapts the apparatus for finer adjustment and for adjustment over a wider range, and what is most important is interchangeable to adapt the apparatus for adjustment as to capacity.

Consider for instance an apparatus of a given size, equipped with a reticulated diaphragm. Assuming that the rate of flame propagation back toward the carburetor is 20 ft. per second, it is obvious that the velocity of the combustion mixture through the diaphragm should be over 2O feet per second in order to keep the flame from resting on the diaphragm and/or clogging or choking the same. This then may be regarded as the minimum velocity of the combustion mixture. Let us assume in this instance that the velocity of the combustion mixture through the diaphragm when the device is operating at full capacity is 120 ft. per second. Now, for the same blower pressure, a venturi placed in the aperture holding the diaphragm will permit the passage of approximately the same quantity of air as the plain aperture. The result is that at maximum capacity the velocity of the combustion mixture through the throat ofa venturi of standard form may befmade to rise as high as 190 ft. per second or more.. A much wider range of regulationV is thus provided for than inthe rst case. In the rst .case the burner rmay be operated between .20 and 120 ft. per second and in the second 'case' it may be operated betweenV 20 and 190 ft. per second.

Any .type of venturi-may be employed for this purpose. I Aprefer to make the venturi removable, thus making the device adjustable for various.' rates of burning and blower pressures.V My experiments have shown that a venturi having dlverging walls which Adefine an angle of about 3 to idegrees with the longitudinalcenterl line, operates very efficiently. Y Iflnd by experience that, even though a reticulated diaphragm is not employed between the venturi and the carburetor, the iiame will be quenched' before it reaches the carburetor; In other words, in my experiments thev flame has been quenched in the throat of the venturi when shutting down. This I believe tov be due to the fact that at very low blower pressures the air velocity at the carburetor jet or jets is so low as to be unable to raise suflicient fuel to form a combustible mixture. Also at'low rates of burning the rate of flame propagation is decreasedl due to leanness of the mixture. However, iffdesired, aireticulated diaphragm maybe placed between the venturi and the carburetor outlet. This reticulated diaphragm will not burn out because it cannot be reached bythe iiame during normal operation, and will not clog because ash and other residue cannot be formed upon it by the burning fuel. Any means maybe provided for holding the venturi in position.

I find it very convenient to provide spark plug housings 13 between sleeve 25 and portion 22. Portion 22 is provided on opposite sides with an aperture 14 to permit passage therethrough of the ends 15 of electrodes 16. 'Ihe venturi 10 is likewise provided with apertures 'i1 to permit the ends 15 to project into the path of the combustible mixture. Electrodes 18 may be conveniently made from spark plugs of the ordinary type by removing the electrode which extends inwardly from the end of the tubular metallic shell. Housings 13 may be provided with screw threads to accommodate the bases of the spark plugs. The apertures 11 are preferably placed slightly toward the diverging side of the venturi throat. This prevents positive ignition on the carburetor side of the ythroat and at theY same time places the electrodes in a position in which they are not contacted by the iiame under normal operation.

Inoperation the electrodes 16 are placed across any source of supply. This is ordinarily the secondary winding of an ignition transformer. Normally the spark jumps from one electrode 18 to the other. Should one of the electrodes become grounded or short-circuited the other electrode will continue in operation because the effect of grounding or short-circuiting one electrode is the same as connecting one side of the transformer winding to the device itself. The spark vin this instance jumps from the remaining electrode 16 to the nearest point which may be the surface of the venturi i8 or the otherv electrode. VThe direct path between electrodes 15 should of' course'bc the shortest.

As a part of the automatic starting and operating equipment I provide a thermostatic switching device. 18 of a well known type, which extends into the tubular member 30. This thermostatic switching device comprises two sealedtubes mounted on a rotating base, each tube containing a. small quantity of mercury.. One end of each tube containsspaced electrodes. The arrangement is such that when the mercury in the tube is in the end containing ther electrodes a 'circuit is closed throughthe electrodes. 'Ihe thermostat elements which rotate the base are so ar'- ranged that when they have been subjected to a predetermined low temperature the mercury in one tube flows into one lof its ends to establish a circuit through its electrodes andwhen the .thermostat elements have been subjected to a predetermined high temperaturethe mercury in the other tube iiows into one of` its ends to establish contact through its electrodes. Inthe interim the circuit through the electrodes of theiirst tube has been broken. In other words at low temperatures a circuit is closed through the first tube only, and at high temperatures a circuit is closed through the second tube only. The arrangement issuch that the second circuit is closed before the iirst is opened. f i

A thermostatic switching device 19 similar to that shown at 18 is placed in the conduit 34 at 80. In other words there is one thermostatic switch-'- ing device on each side of the heating element 45. The operation of the heating element 45 will` be hereinafter described. r

Carburetor 39 is provided with a fuel inlet pipe 8i connected to any source of supply. Pipe8lis provided with a valve 82. Carburetor 39 is also provided with a drain pipeV 83 having a valve 84. Pipe 83 leads to any suitable receptacle not shown. A tubular projection such asthat illustrated at 85 may be provided to permit` the insertion of a thermometer 86 into conduit 34 to determine the temperature of the air flowing therethrough.

The carburetor 39 is, of course, provided with the suitable butterfly valve 81. I

Receptacle 62 is provided with a iioat 88 which controls an electrical switch 89 for establishing a circuit to electromagnetic valves 82 and 84. The arrangement is such that when the float 88 is at the bottom of thev receptacle 82 a circuit is closed through the switch 89. When the float 88raises,` the circuit through switch 89 is broken. Fuel valve 82 opens with a iiow of current and drain valves 84 closeswith a flow of current and' vice versa.

The thermostatic switching devices-18 and 19 and valves 82 and 84 together with the associatedr mechanism are part of the automatic starting and operating system and may or'may not be used as desired. The operation of the burner without the automatic starting and operating mechanism is 'as follows:

The carburetor float chamber is rst drained of all fuel.V V'Ihe switches (not shown) leading to the heating element 45 and to ra suitable transformer for electrodes 16 are now closed. The blower is started and the carburetor butterfly 81 is opened very slightly so as to permit only a small quantity of air tov pass. In a very short time'the'air passing heating element 45 is heated to a temperature which is sufliciently high to cause vaporization of' the fuel. 'Ihe choke valve 65 is nowv partially closed. Fuel is then admitted into the carburetor iloatchamber. Ignition of the combustion mixture takes place almost immediately. vThe flame shoots outwardiy from the venturi 18 intofthecombustion. chamber l2; rais- III ing the temperature'of thesame. Heating of the combustion chamber I2 in turnl heats the air passing through the air passage I5. The choke valve 65 can now be completely opened, thus placing it out,of use. In a relatively short time'the flame will furnish sufficient heat to the combustion chamber I2 to heat the air in air passage I5 to a temperature to permit operation without the help of heating element 45. Ignition having been well established, the switch (not shown) leading to the heating element 45 and to a suitable transformer may now be opened. The device is now properly warmed up andthe amount of fuel consumed may be regulated by the carburetor valve 81. This regulation may be manual or automatic.

After the fuel reaches the proper level in carburetor 39 it begins to flow up into jet or jets 58 and isvaporized by the flowing air. The resulting combustible mixture is ignited as it passes through venturi 10 by the spark passing between electrodes 16.

The flame begins to heat combustion chamber I2 which in turn begins to heat the air passing through air passage I5. When the air passing through the air passage I5 reaches a desired temperature, suitable in itself for proper vaporization of fuel, it actuates thermostatic switching device 18 causing it to turn clockwise bringing the tubes 96 and 91 into the positions shown in dotted lines.

The turning of the thermostatic switching device 1'8 signifies that the device is properly warmed up and that the rate of combustion may be increased to meet requirements.

If, after the burner is in operation, the flame should become extinguished for any reason, combustion chamber I2 will begin to cool, thus failing to heat the air passing about it to the required temperature to hold thermostatic switching device 18 in its clockwise position. Thermostatic switching device 18 will then turn counterclockwise back to its starting'position, opening the circuit throughtube 91which in turn breaks the circuits through fuel valve 82 and drain valve 84 causing the fuel valve 82 to close and the drain valve 84 to open. Flame extinction will cause thermostatic switching device 19 to return to its original position which will also break the' circuit through valves 82 and 84.

Any irregularities in the float chamber of the carburetor causing excess fuel to overflow through pipe into receptacle 62 will cause fioat 88 to rise, so as to open the circuit through valves 82 and 84 to shut off the supply of fuel and to drain the carburetor. The shutting off ofthe fuel supply extinguishes the fiame and the device shuts down as described in the previous paragraph.

It can be readilyseen that it is impossible to start and operate the device except under normal conditions. If any difficulty should arise, such difficulty must be entirely removed before the burner can be restarted. For instance, fuel difficulties causing the float 88 to rise in receptacle 62 requires the receptacle to be drained before switch 89 will be returned to normal position. The operator of course, will at once realize that the cause of the overflow of fuel must also be immediately corrected.

Ignition difficulties will prevent thermostatic switching device 18 from turning clockwise or will cause this thermostatto return to its original position, in either event the device will be shut down.

, Failure of the heating element 45 will prevent thermostatic switching Vdevice 19 from turning clockwise. This will prevent fuel from being delivered to the carburetor 39.

While the invention has been described in connection with liquid fuels itis understood that the same is applicable to burning of fuels of any character such as gaseous fuels or semi solid or solid fuels. The latter may be comminuted or volatile in character or otherwise.

Many other changes may be made in the hookup or in other parts of the device without departing from the spirit of the invention. For instance thermostatic switching device 18 may be placed on the same sideof` the heating element as thermostatic switching device 18 by having thermostatic switching device 18 operate at a temperature above that capable of being supplied by the heating element but capable of being supplied by air passage I5.

My novel burner has been illustrated as operating in horizontal position. However, it is to be understood that it may operate at any angle provided the' fuel mixing device is adapted thereto.

Having described my invention, it is obvious that many modications may be made in the same within the scope of the claims without departing from the spirit thereof.

. I claim:

1. In a device for burning fuel, a mixing chamber for air and said fuel, a combustion chamber for burningv a mixture of said air and fuel, an air passageway in heat exchange relationship with said combustionY chamber, a Venturi metering and mixing device for said fuel and air arranged in direct communication with said passageway so that the air flowing through said passageway and subject to the heat of said combustion chamber is the only air available and the only air used for operating, and carrying the resulting air and fuel mixture from, the metering and mixing device, a second venturi adjacent said combustion chamber and provided with associated ignition means, said last named venturi being adapted to prevent the passage of a flame therethrough, said venturis being substantially spaced from each other and said mixing chamber being arranged therebetween'.

2. A device of the kind described, comprising a combustion chamber, means for forming a combustible mixture, said means comprising an inlet for fuel, a Venturi metering and mixing device for air and said fuel, an inlet for air and an air passageway vsubject to the heat of combustion in said combustion chamber, said metering and mixing device being in communication with said air passageway so that they air therein subject to the heat generated in said combustion chamber is the only air available and utilized for operating, and carrying the mixture from, said meteringandmixing device, means for delivering said combustible mixture to said combustion chamber, and means forpreventing fiame propagation from said combustion chamber back to said combustible mixture forming means, said fiamepropagation preventing means comprising a venturi positioned in the path of said combustible mixture between said combustion chamber and said v combustible mixture forming means, said venturi having a throat of a cross sectional area suiiiciently small to increase the speed of said combustible mixture to a` point at least as. high as any rate of flame propagation of said combustible mixture during normal operation of said device.

3. In a device of the kind described, a combustion chamber, means for forming a combustible mixture and for delivering the same to said combustion chamber, said means comprising an inlet for fuel, a Venturi metering and mixing device for air and said fuel, an inlet for air and an air passageway subject to the heat of combustion in said combustion chamber, said metering and mixing device being in communication with said air passageway so that the air therein subject to the heat generated in said combustion chamber is the only air available and utilized for operating, and carrying the mixture from, said metering and mixing device, a second venturi between said first mentioned means and said combustion chamber, said second venturi positioned in the path of said combustible mixture so as to cause all of said combustible mixture to pass therethrough, said second venturi preventing flame propagation therethrough during normal operation of said device.

4. In a device of the kind described, a homogenizing chamber, means including a venturi for metering and mixing liquid fuel with air, an air passageway in heat exchange relationship with said combustion chamber, said venturi being in communication with said air passageway so that the air in said passageway subject to the heat generated in said combustion chamber is the only air available and utilized for operating, and carrying the mixture of air and fuel from, said venturi, a second venturi adapted to prevent flame propagation therethrough during normal operation of said device, said homogenizing chamber interposed between and connecting said rst and second mentioned venturis, and means in said second venturi on the outlet side of the throat thereof for igniting said vaporized fuel.

JEROME J. SLOYA'N. 

